package com.github.shiqiyue.rate.limiter.utils;

import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
import org.springframework.util.StringUtils;

import javax.servlet.http.HttpServletRequest;

/***
 * ip工具类
 *
 * @author kjq
 *
 */
public class IpUtils {
	
	private static final Logger log = LoggerFactory.getLogger(IpUtils.class);
	
	private static final String LOCALHOST_IPV4 = "127.0.0.1";
	
	private static final String LOCALHOST_IPV6 = "0:0:0:0:0:0:0:1";
	
	private static final String UNKNOW = "unknown";
	
	/**
	 * 获取IP地址
	 *
	 * 使用Nginx等反向代理软件， 则不能通过request.getRemoteAddr()获取IP地址
	 * 如果使用了多级反向代理的话，X-Forwarded-For的值并不止一个，而是一串IP地址，X-Forwarded-For中第一个非unknown的有效IP字符串，则为真实IP地址
	 */
	public static String getIpAddr(HttpServletRequest request) {
		String ip = null;
		try {
			ip = request.getHeader("x-forwarded-for");
			if (StringUtils.isEmpty(ip) || UNKNOW.equalsIgnoreCase(ip)) {
				ip = request.getHeader("Proxy-Client-IP");
			}
			if (StringUtils.isEmpty(ip) || ip.length() == 0 || "unknown".equalsIgnoreCase(ip)) {
				ip = request.getHeader("WL-Proxy-Client-IP");
			}
			if (StringUtils.isEmpty(ip) || UNKNOW.equalsIgnoreCase(ip)) {
				ip = request.getHeader("HTTP_CLIENT_IP");
			}
			if (StringUtils.isEmpty(ip) || UNKNOW.equalsIgnoreCase(ip)) {
				ip = request.getHeader("HTTP_X_FORWARDED_FOR");
			}
			if (StringUtils.isEmpty(ip) || UNKNOW.equalsIgnoreCase(ip)) {
				ip = request.getRemoteAddr();
			}
		} catch (Exception e) {
			log.error("IPUtils ERROR ", e);
		}
		
		// 使用代理，则获取第一个IP地址
		if (!StringUtils.isEmpty(ip) && ip.length() > 15) {
			if (ip.indexOf(",") > 0) {
				ip = ip.substring(0, ip.indexOf(","));
			}
		}
		
		return LOCALHOST_IPV6.equals(ip) ? LOCALHOST_IPV4 : ip;
	}
}
